The present invention relates generally to communication systems and, in particular, to providing communication services to communication units in wireless communication systems with overlapping coverage areas.
In wireless communication systems, service requests, such as call requests, made by a communication unit to a base site providing service to the communication unit can be blocked if the base site does not have sufficient resources to support the service. Some wireless systems, such as analog cellular systems, provide a directed retry feature to address this problem. In wireless systems in which the wireless coverage areas of base sites significantly overlap, directed retry directs the service request to a neighboring base site. Thus, when a communication unit""s serving site does not have sufficient resources but a neighboring site does, the communication unit can obtain communication service from the neighboring base site rather than being blocked by the serving site.
A shortcoming of directed retry, however, is that the communication service provided by the neighboring base site may have poor or insufficient audio quality. For example, a call request is granted by a neighboring base site, but the audio quality is so poor that the user must often repeat herself, end the call in frustration, or redial after the call is dropped by the system. Thus, a need exists for an apparatus and method for providing a communication service to a communication unit with acceptable audio quality, when a serving site does not have sufficient resources.